Ratchet mechanism



F. H. SLHWERIN.

RATCHET MECHANISM.

APPLICATION FILED ocr.22,191s.

Patented Jan. 10, 1922.

2 SHEES SHEET l.

A TTHNE Y 1919. Patented Jan. 10, 1922 EETS-SHEET 2.

purr MANUFACTURING 'oor/IPANY, or

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uPT'lSBUGH, PENNSYLVANIA, A CORPO- Ptamcnnr MEGHANIsr/r.

Specification of lIletters'latent.

Application inea october 22, 191e. serial No. 332,465.

To all whom t may concern.'

Be it known that I, FRANK H. SCHWERIN, a citizen of the United States, and resident of the borough of West View, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Ratchet Mechanism, of which the following is a specification.

The invention relates to pawl and ratchet mechanisms, and particularly to powerapplying pawl-and-ratchets such as are used in jacks where heavy resistance is to be overcome. For adequate strength and in order to guard against accident in event of the breaking of a tooth, these mechanisms areso designed that a plurality of teeth on the pawl, usually three, at different distances' from the center, act simultaneously on a corresponding number of teeth on the ratchet wheel, but as such mechanisms have been heretofore constructed, serious diiiiculty has been experienced with the pawl tending to slip out of engagement, necessitating the use of a heavy holding spring, which is liable to fail. The purpose of the present invention` is to overcome this ditliculty, at the same time increasing the strength of the mechanism by reason of the form and cooperation of the parts, and while providing a form of the ratchet which can be economically cut.

Inthe accompanying drawings, forming a part hereof: y

Fig. 1 is a side elevation of a pawl-andratchet mechanism embodying the invention, showing the pawl held out of action;

Fig. 2 is a front elevation;

Fig. 3 is a section in the central plane normal to the centers, illustrating the action on the reverse or idle movement of the rocker and pawl;

Fi et is an end view, looking at the mouth of the socket; and u Fig. 5 is an enlarged View corresponding to the lower part of Fig. 3 showing the relation on the working stroke, certain radii and perpendiculars being represented by broken lines.

rlhe numeral 1 designates the shaft to which power is intermittingly applied in the direction of the arrow of Fig. 5; 2 is the ratchet wheel keyed on an angular portion of this shaft, and 3 is an ordinary rocker oscillatable upon the shaft, having cheek portions 4f embracing the ratchet and e handie-receiving socket 5. The pawl 6 is pivoted between the cheeks of the rocker on a transverse pin 7. with a series of teeth 8, at one side of the line of centers, formed and arranged to engage simultaneously with a corresponding numberk of teeth 9 on the ratchet.

12 is an ordinary plunger in a spring-barrel 13 on the rocker, cooperative with a notch 14 in the end of the pawl to hold the same in an outward-tilted, inoperative position when desired; and 15 is a comparatively light spring in the barrel for pressing the plunger outward. When the pawl is moved inward until the crest 16 passes the center of the plunger tip, the plunger and spring by actlng upon a slope 17 automatically throw the pawl into complete engagement. Heretofore a much heavier spring in a similar location has been relied upon to hold the pawl in, during the working stroke, but as will presently appear this is not necessary under the present invention, and a positive holding is substituted, which becomes the more vforcible 4the greater the power that is applied to turn the mechanism.

rlhe teeth 9 of the ratchet are of buttress formation, being deeply triangular in the circumferential direction, with low sloping backs 10 and abrupt working faces 11. As shown more clearly in Fig. 5, said working facesare inclined slightly forward of the radii drawn to the ends of the teeth. rlhe plural teeth 8 of the ratchet are of similar nature, reversed to the teeth of the pawl, and the form and arrangement are such that in the working condition the teeth of the two parts fit back to back and face to face. A vit-al feature of the invention resides in the fact that all or substantially all perpendiculars to the working faces in action pass between the centers, that is to say the center of rotation of the ratchet and rocker on the one hand and the pivotal center of the pawl on the other. This is represented in Fig. 5.

With this construction, when power is applied, there is a component of pressure between the teeth which acts to draw or wedge the several teeth of the pawl inwardly of the ratchet, thereby preventing all possibility of flying out. Moreover, the form of the teeth and the mutual support resulting from the fitting abutment of their sloping backs, and the wedged engagement as aforesaid,

This pawl is provided` Patented Jan. 1G?, 1922.

renders the teeth practically proof 'against breakage. When the rocker is swung backward on the idlestroke, all of the vteeth lin engagement pass freely,as seen in Fg.-3.

5 A ratchet wheel formed as described, is sus-` ceptible of manufacture bya cheap hobbing process, and-need notvbe milled.

What I claim as new lis :v

In a pawlandratchet mechanism, the

V10 combination of a Vratchet having buttress teeth the working faces of which incline slightly forward of the radii of their tips, and a pivoted pawl having a yseries of; reversely arranged ,buttressfteeth formed to engage simultaneously a corresponding number of teeth on the ratchet, the relation being such that substantially all pcrpendiculars to the working faces in action pass between the centers.

`FRANK H. SCHWERIN. 

